Greetings from Greasy Corner, Arkansas.
This is my f irst post on this site. I am doing research for a book, and I feel the vast and extensive knowledge of the members can help.
What I need to know is.
1. Was the Grafliex 5x7 available in Scotland and subsequently into France in WW1?
2. Did the camera use double dark slides holding film, or were glass plates in use?
3. How easy would it have been to use hand-held and would changing film inthe field pose many problems?
4. Could someone please tell about the lens in use, and how it worked?
5. Who manufactured the film for this camera circa 1916?
Any other information consider relevant.
Thank you in advance for all assistance.
ArthurT.

I have no aversion to being a source of innocent amusement to the Graflex historians on this site, so I'll start the ball rolling with some vague and, perhaps, inaccurate generalities.

I'm sure that someone in Scotland, or elsewhere in the United Kingdom, could have gotten a 5x7 "Speed Graphic" in 1916. Similarly, I suppose you could have obtained one in France, if you'd wanted one -- you might have had to send away for it, but people did that all the time.

It might be fun to find out whether the unavailability in Britain and France (etc.) of new German cameras after August, 1914 emcouraged U.S. manufacturers to try expanding the export of our lower-priced alternatives to the beautiful but pricey English cameras that then dominated the high end of the market.

I'd be surprised if many combat photographers would have wanted to use a 5x7 camera of any make. My impression is that the German press corps tended to use 9x12-cm. format cameras (e.g., the Goerz "Anschutz") and I'd expect British (or American) photojournalists and military photographers to favor models accepting 3-1/4x4-1/4 or 4x5 materials. A 5x7 "Speed Graphic" might have been a very good choice for an observer in a captive balloon.

The photographer would have had a choice of cut film, roll film (including much larger sizes than are available now), film pack (which I think was invented in or before 1912) or dry plates -- for that matter, wet plates, if he'd wanted to carry a Matthew Brady-style tent or wagon around with him. (Wet collodion remained popular for graphic arts work through the 1930s.)

If I thought someone were likely to shoot at me while I was using a camera, I'd opt for film pack, which gave you a lot of exposures in a compact package, and was very quick and easy to advance. On this reasoning, dry plates would not have been a popular choice. The idea would be to have things in your pockets that wouldn't break into sharp pieces if you need to jump into a hole.

If the photographer were English, he'd be likely to use one of the excellent lenses available from Taylor, Taylor & Hobson (e.g., the "Cooke Anastigmat"), Ross, Dallmeyer or others. If he'd bought his lens before the outbreak of hostilities, it might be a Goerz "Dagor" double anastigmat or Zeiss "Protar" or "Tessar." He also could be using one of the older but still popular "Rapid Rectilinear" lenses, which were made under various names by several manufacturers (in the U.S., Bausch & Lomb. B&L also had a license to make "Protars"; so, I think, did Ross in England, and an outfit in France, perhaps Krauss).

My guess on film would be Eastman Kodak Co. for the United States (it showed everybody the way, and developed an international presence before WWI). Or, perhaps, Kodak's great rival Anthony & Scoville (later Ansco), and maybe Ilford in England. It was a lot easier to be a film manufacturer back then (easier still to make dry plates), so there may well have been a number of long-forgotten producers.

...I observe that you said "Graflex." These surely were around (in 5x7 and smaller sizes during World War I. They had many British competitors, made by famous manufacturers like Adams, Thornton Pickard and Marion (and more besides). They were widely used for peaceful reportage, but would not have found favor in a battlefield setting because you really had to use them standing up, and they did not fold up readily (though I think the Adams "Minex" collapsed more than a "Graflex" did).

I think the British Army was contracting for Marion "Soho Reflex" cameras right through World War II, but I doubt that the intended use was combat photography. You really wanted something with an eye-level finder for that!

Concerning how the lens might have worked: if the camera were a "Graflex" reflex, the lens would have had a conventional iris diaphragm and nothing more. You focused with the lens wide open so you could see the image on the groundglass, then reached around and stopped down (if necessary) before making the exposure.

If it were a "Speed Graphic," the lens might have been mounted in a shutter but, at that time, probably would not have been. The appeal of the early "Speed Graphic" was its reliable, fast focal plane shutter. Front shutters with any kind of accuracy and versatility were still in their infancy, although the early modern "Ilex" and Daeckel "Compur" (derived from the design licensed from Ilex) both predate the outbreak of war (1910 and 1912, I think).

It always has been a mystery to me why no one fitted an automatic diaphragm to the lens of a large-format reflex prior to the 1950s. Jason Schneider of "Popular Photography" (and earlier, "Modern") once reported that Graflex patented an automatic diaphragm system in the 1920s. For some unknown reason, this seems not to have been incorporated into a real-world lens until the '50s.

I suppose it's all in what you are accustomed to; I've always had enough trouble with "preset" diaphragms, but my early experience was with rangefinder cameras.